3. Nervous System Flashcards
Mental Status
- Physical Appearance
- Communication
- Level of consciousness (GCS)
- Cognitive Abilities & Mentation
Sensory Assessment
- Interoceptive Sensation
- Proprioceptive Sensation
Cranial Nerve Assessment
- All 12 cranial nerves
- Oculomotor nerve (Pupillary Reflex)
Motor System Assessment
- Muscle size
- Muscle tone
- Muscle strength
- Involuntary Movements
- Pronator drift
Cerebella Function
- Coordination
- Station
- Gait
CNS
Central Nervous System:
Brain + Spinal Cord
PNS
Peripheral Nervous System:
- Cranial nerves
- Spinal nerves
- Ganglia
- Enteric plexuses (in small intestine)
- Sensory receptors (in skin)
Sensory (Afferent)
Signal that comes in
Motor (Efferent)
Signal exits the spinal cord
Somatic vs. autonomic
Voluntary vs. Involuntary
Sympathetic vs. Parasympathetic
Flight or flight vs. rest & digest
“P for peaceful”
Dual Innervation
serve the same visceral organs but cause opposite effect
Parasympathetic Division
- Keeps body energy as low as possible
- “house keeping activities,” e.g. digestion, elimination of waste, etc.
Sympathetic division
- Activates when we are excited or threatened
- Temporarily dampens nonessential activities
Functional Cells
Neurons
- Electrically excitable cells
- Cannot multiply or divide
- 50% of nervous system cells
Support Cells
Glial Cells (Neuroglia)
- Not electrically excitable
- Can multiply & divide
- 50% of nervous system
Dendrites
Soma
“The lollipop”
Axon
Tail of
Axon Hilock
Junction between
Axon Terminal
Where the axon ends
Schwann Cell (Neurolemmocyte)
Produces cover around the axon of the neuron, myelin sheath
Multipolar Neuron
Motor neuron
Process of Myelination
Myelin sheath (fatty material) electrically insulates the axon of a neuron increases the speed of the impulse.
PNS: Schwann Cells
(can myelinate only one cell)
CNS: Oligodendrocytes
(can myelinate several cells)
4 Different Regions of the Brain
- Cerebral Hemispheres (Cerebrum)
- Gyrus (Ridges) & Sulcus (Valley) - Diencephalon
- Brain Stem
- Cerebellum (small brain)
5 Lobes of the Brain
- Frontal
- Parietal
- Occipital
- Temporal
- Insula
Frontal Lobe
“Makes you you.”
Personality
Higher order
Executive Function
Parietal Lobe
Integrating environmental information
Occipital Lobe
Vision
Temporal Lobe
Hearing
3 Divisions of Diencephalon
THE diencephalon
- Thalamus
- Hypothalamus
- Epithalamus
Thalamus
Sorting incoming information
Hypothalamus
Hormone regulation
Epithalamus
Sleep/wake cycle
Cerebellum
-Heavily folded: folia
-Precise muscle contraction
(Figures out how to reach out and grab a pen, planned by frontal lobe)
Brainsteam
Includes: (MPM) midbrain, pons & medulla oblongata.
Regulation of basic functions: heart rate, breathing, etc
Circle of Willis
Links anterior & posterior blood supplies
How much of the body’s oxygen supply does the brain use?
20%
Blood-brain Barrier (BBB)
Protects brain cells from harmful substances and pathogens
3 Layers Meniges
PAD
- Pai Mater (soft mother)
- Arachnoid Mater (spider mother)
- Dura Mater (tough mother)
Choroid Plexus
Where CSF is produced
Where is foramen magnum
“Big hole”
L1/L2
Posterior/Dorsal Root
Sensory information comes through here into the spinal cord after the posterior/dorsal ganglion (bulge/collection of neuron heads)
Ventral/Anterior Root
Commands come out here from spinal cord
Grey Matter vs. White Matter
Larger concentration of soma vs. axons
Where is an LP performed?
L3/L4 or L5/L5
Cranial Nerve X (Vagus)
- 2 mixed cranial nerves
- originate from medulla
- carry motor signals to lungs, heart & digestive organs
Spinal Nerves
- Connects CNS to sensory receptors, muscles and glands
- 31 Pairs
- All nerves are mixed
Regions of the Spinal Nerves
- Cervical
- Thoracic
- Lumbar
- Sacral
- Coccygeal
Connective Tissue Covering Nerve
- Endoneurium
- Perineurium
- Epineurium
Nerve Plexuses
Redundant nerves in interconnecting plexuses; helps to prevent total loss of motor functions with a spinal injury.
Where does sympathetic motor neurons exit the CNS?
Thoracic & Lumbar regions
Noradrenalin
Used by second motor neuron as the neurotransmitter to stimulate target tissue
Where does parasympathetic motor neurons exit from?
Brainstem and sacral part of spinal cord
Acetylcholine
ACh
The major neurotransmitter for parasympathetic division?
Percentage of parasympathetic motor neurons that are in the vagus (X) nerve
80%
Ganglion
“Head” of neuron
Sympathetic
🟢🟩🟩🟩🟢 X 🟢🟩🟩🟩🟢Y
Pre-ganglionic Post-ganglionic
X= ACh Y= NA
Parasympathetic
🟢🟩🟩🟩🟢 X 🟢🟩🟩🟩🟢Y
Pre-ganglionic Post-ganglionic
X= ACh Y= ACh
(Somatic nervous system) single neuron from CNS to effector organs
🟡🟦🟦🟦🟦🟦🟦🟦🟦🟠 X
ACh
Action Potential vs. Graded Potential
AP allow communication over short and long distances.
GP allow communication over short distance only.
Production of AP or a GP depends on existence of a resting membrane potential and the existence of certain ion channels.
Resting Membrane Potential (RMP)
RMP is difference in electrical potential on either side of PM.
What determines that the membrane in a non-conducting neuron is (+) outside and (-) inside?
- Unequal distribution of ions across the PM and the selective permeability of the neurons membrane to Na+ and K+.
- Most anions cannot leave the cell.
- Na+/K+ pumps.
Distribution of Cl-, Na+, PO4- & K+ in resting membrane potential
“You’re O-K at home.”
Cl- Na+ 🔵🔵🔵🔵🔵🔵 ◻️◻️◻️◻️◻️◻️ 🔵🔵🔵🔵🔵🔵 PO4- K+
Overall charge inside neuron cell
Negative, because of protein & DNA, despite overload of K+
Threshold Potential
The point of no return [At -55 mV] enough Na+ comes into cell making it more and more positive (Na+ influx/depolarization) until it reaches a certain +30 mV causing K to leave the cell (K- efflux/repolarization) making it more negative until it passes -70mV to -90-100mV and then readjusts back to resting -70mV (After-hyperpolarization phase).
Factors that affect propagation
- Axon diameter
- Amount of myelination
- Temperature
Continuous vs. Saltatory Conductuon
W/o myeliantion vs. w/ myelination sheath
Synaptic vesicles
A vesicle that carries molecule from pre-synaptic neuron to post-synaptic neuron
Charge of neuron at rest
-70 mV
White Matter
Conducts nerve impulses to and from the brain
Grey Matter
Receives and integrates incoming and outgoing information to perform spinal reflexes
